oil leak between oil pan and timing cover

[old Chevy guy]

The problem was the need for the thicker front pan seal. The old pan measured like that too so not sure if the old pan was already a replacement of if my engine is really newer than I thought. Always thought it was the original . It has a two barrel on it which I figured out recently was not correct for a 71 with a 350 but figured somebody swapped the intake, now who knows? I will have to get the numbers and decode it and see what's up with that. When I changed the rear main the directions said to offset the ends also. The research I did on the oil pan issue said that the break year for that change was 1975 and up had the fat one but that was the only difference in the pan gasket. I also threw in a new chain and gears which I failed to do before. Upon closer inspection its a good thing as the original nylon was all cracked.